In recent years, surface mount device technology (SMDT) has become prevalent in the electronics industry. Surface mount devices (SMDs) and printed circuit boards using this technology have a series of solder pads thereon. To mount the SMDs to the printed circuit board, a solder paste is applied on the solder pad of the printed circuit board typically by screen printing or stencil printing. The surface mount device is placed on top of the solder paste. The solder paste is heated to reflow the solder and join the solder pads on the SMD with the solder pads on the printed circuit board. Adhesives may be used to retain the SMDs in position during the solder reflow process.
A problem that is often encountered in the fabrication of printed circuit boards using surface mount technology is warped printed circuit boards. Circuit board manufacturers usually allow a tolerance of 0.060 inches variance from one corner to a diagonally opposite corner of the board. When heat is applied to the board during the solder reflow process, additional warping may occur. Warping of the printed circuit board has an adverse affect on yields because it directly affects other parts of the fabrication process. For example, capacitors and resistors are very small, typically 0.040.times.0.020 inches. If a board is warped, the components can bounce off or drop inaccurately onto the printed circuit board. Warped boards effect coplanarity of components, x-y origin offsets, and repeatability of component placement. It is therefore desirable to devise new methods of thicker board fabrication which effectively deals with the problem of board warping. A solution to this problem would result in greater yields and a concomitant reduction in cost of manufacturing of printed circuit boards.